<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
</head>
<body>
  <!-- 
    align-self: 单独设置item的对齐方式
                属性值遵从,align-items
                会覆盖align-items的设置
  -->
  <style>
    .align-self{
      display: flex;
      height: 300px;
      border: 1px solid;
      align-items: flex-end;
    }
    .align-self div{
      height: 50px;
      width: 50px;
      background-color: pink;
      border: 1px solid;
    }
    .self{
      align-self: center;
    }
  </style>
  <div class="align-self">
    <div></div>
    <div class="self"></div>
    <div></div>
  </div>
</body>
</html>